1. Field of the Invention
The invention relates to a parking lock device that locks a shaft connecting to wheels to prevent a vehicle from moving when the vehicle is parked.
2. Description of Related Art
A parking lock device of a vehicle has a gear that is fixed to a shaft connecting to wheels, and a lock that is engaged in a tooth space of the gear to lock the gear. It should be noted herein that the shaft connecting to the wheels means a shaft that rotates while establishing a relationship of being constantly fixed to the wheels. The gear is locked to lock the wheels, thereby preventing the vehicle from moving when the vehicle is parked.
The parking lock device is provided in a transmission of the vehicle. The transmission is a device that has a function of converting rotational speeds and torques of outputs of prime movers such as an internal combustion engine, an electric motor and the like, which are mounted on the vehicle, and delivering the outputs to the wheels. There is also known a device that is equipped with a differential for permitting a difference in rotational speed between right and left driving wheels as well as a shifting mechanism that carries out speed conversion and torque conversion. Examples of the transmission include, for example, a manual multistage transmission, an automatic multistage transmission, and a continuously variable transmission. Besides, there is also known a transmission for a hybrid vehicle that also incorporates an electric motor for driving the vehicle in addition to a shifting mechanism.
An example of the configuration of a parking lock device of a vehicle is disclosed in Japanese Patent Application Publication No. 2006-131109 (JP-2006-131109 A).